Multi-pole electric circuit breaker and fuse combination with single blownfuse sensing solenoid for all poles



March 14, 1967 w, K|E5EL ET AL MULTI-POLE ELECTRIC CIRCUIT BREAKER AND FUSE COMBINATION WITH SINGLE BLOWN-FUSE SENSING SOLENOID FOR ALL POLES Filed Sept. 15, 1965 CI Z/ I N VENTOR 3 United States Patent Ofiice 3,309,478 Patented Mar. 1 1-, 1967 3,309,478 MULTI-POLE ELECTRIC CIRCUIT BREAKER AND FUSE COMBINATION WITH SINGLE BLOWN- FUSE SENSING SOLENOID FOR ALL POLES George W. Kiesel and Henry E. S. Owen, Unionville,

Conn., assignors to General Electric Company, a corporation of New York Filed Sept. 15, 1965, Ser. No. 487,424 '1 Claim. (Cl. 200-114) Our invention relates to electric circuit breaker and fuse combinations, and more particularly to multipole circuit breaker fuse combinations.

When electric fuses are used in conjunction with electric circuit breakers, it is' desirable to provide means whereby the circuit breaker will be caused to open whenever one or more of the fuses blows. In accordance with the prior art, such arrangements have included a trip means for the circuit breaker and an electric solenoid for each pole of the multipole device, arranged so that the solenoid is energized whenever the fuse blows. In the past, these arrangements have been such as to require the use of a separate solenoid for each of the fuses utilized, and is therefore relatively expensive and also requires a substantial amount of room within the circuit breaker casing.

It is an abject of the present invention to provide a multipole circuit breaker and fuse combination wherein the blowing of any one of a plurality of fuses causes a single solenoid to be energized causing tripping of the circuit breaker.

It is a further object of the invention to provide a multipole circuit breaker fuse combination which is dependable and compact and which also does not require the use of auxiliary contacts.

In accordance with the invention in one form, a multi pole fuse circuit breaker combination is provided including an electric circuit breaker having movable contacts and an operating mechanism, which operating mechanism includes latch means operable to cause automatic opening of the contacts. An electric fuse is connected in series with each pole of the circuit breaker. In addition, a multi-coil solenoid is provided having a single actuating plunger and separate energizing coils corresponding to the number of fuses utilized. Accordingly, whenever one of the fuses blows, current is diverted through the corresponding winding, energizing the solenoid and causing automatic opening of the circuit breaker.

In another aspect of the invention, separate switch means is provided in series with each of the coils of the solenoid so that, when desired, one or more selected coils may be disconnected, such for example as to permit single phase operation, in a manner to be described.

In the drawings,

FIGURE 1 is a side elevation View of a multipole electric circuit breaker-fuse combination incorporating the invention;

FIGURE 2 is a diagrammatic representation of the electrical connections of the circuit breaker of FIGURE 1;

FIGURE 3 is a diagrammatic representation of another form of the invention.

Referring to FIGURE 1, the invention is shown as incorporated in a multipole electric circuit breaker fuse combination comprising a circuit breaker portion and a fuse-containing compartment 11. While the fuse compartment 11 is shown as directly adjoining the circuit breaker 10, it will be understood that the fuse compartment 11 may, if desired, be spaced any desired distance from the circuit breaker 10.

The circuit breaker 10 includes incoming line terminals 13 (FIGS. 2 and 3) and outgoing load terminals 12,

which are arranged to be connected or disconnected by movable contacts 14 operated by suitable operating mechanism. The operating mechanism preferably includes manual operating means for moving the contacts between open and closed circuit positions, and also automatically operable means for moving contacts to open circuit position upon the occurrence of predetermined conditions. An operating mechanism of the type described is shown, for example, in Patent No. 3,158,717, Iencks et al., issued November 24, 1964 and assigned to the same assignee as the present invention.

The circuit breaker operating mechanism, as shown in FIG. 1, includes a releasable member 15 normally restrained by an intermediate latch 16 which in turn is restrained by a latch member 17 carried by a common trip bar 18. The common trip bar 18 is disposed to be actuated by current responsive means, not shown, connected in circuit with each pole of the circuit breaker.

Referring to FIGURE 2, a plurality of electric fuses 20 are connected each in series relation with one pole of the circuit breaker 10, between the terminals 13 and a spaced set of terminals 21. In FIGURE 2, the contacts 14 are shown semi-diagrammatically as restrained in the closed circuit position by a releasable member 22 biased toward releasing position by biasing means 23, and restrained from movement in releasing direction by latch member 24, pivotally supported at 25.

In accordance with the invention, a solenoid indicated generally at 26 is further provided, having a plurality of coils 27, 28, 29. Each of the coils 27, 28, 29 is connected across a corresponding one of the fuses 20. The solenoid 26 further includes an operating plunger 30 disposed and arranged to be attracted and to strike the latch member 25 when any one of the coils 27, 28, 29 is energized.

The form of the invention shown in FIGURE 3 is similar to that of FIGURE 2 with the exception that in this form a plurality of switches 35 are provided, each in series with one of the coils 27, 28, 29 respectively. The switches 35 are all normally closed. In the event of a short circuit condition which causes one of the fuses 20 to blow, the corresponding winding 27, 28-, 29 will be energized causing tripping of the circuit breaker in the manner previously described. In some cases, such for example as when a three-phase motor is being operated and emergency conditions warrant it, or when the load on the circuit breaker comprises only an electrical lighting load, it may be desired to maintain the circuit breaker closed despite the fact the one fuse has blown. For this purpose, the corresponding coil of the solenoid 26 can be disconnected by opening the corresponding switch 35, thereby permitting continued operation of two phases or two poles only.

While the invention has been shown in only two embodiments, it will readily be appreciated that many modifications thereof may be made, and we therefore intend by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

A multipole electric circuit breaker and fuse combination comprising:

(a) a three-pole electric circuit breaker, said circuit breaker including an insulating base;

(b) three pairs of relatively movable contacts supported on said insulated base;

(c) operating mechanism supported on said insulating base;

(d) means connecting said operating mechanism to said pairs of contacts for moving said contacts between open and closed circuit positions, said operating mechanism including a trip member and means biasing said trip member toward open circuit position and a latch member normally restraining said trip member in closed circuit position;

(c) three electric fuses, each of said fuses being connected electrically in series with one of said pairs of relatively movable contacts;

(f) an electric solenoid supported on said base, said solenoid comprising three separate windings, each of said windings being connected electrically in parallel with one of said fuses respectively;

(g) said solenoid including an actuating plunger disposed to be actuated upon energization of any of said solenoid windings, whereby upon blowing of at least one of said fuses, the corresponding one of said windings is energized, actuating said solenoid plunger and causing release of said latch member and opening movement of all of said contacts; and

(h) switch means electrically in series with each of said windings of said solenoid whereby said windings may be selectively disconnected, whereby said circuit breaker is maintained in said closed condition despite the blowing of one or more of said fuses.

References Cited by the Examiner UNITED STATES PATENTS 1,288,820 12/1918 Braunwarth 200-88 3,045,167 7/1962 Colaiaco 31726 X References Cited by the Applicant UNITED STATES PATENTS 971,082 9/1910 Sessions. 1,259,202 3/ 1918 Baruch. 1,702,454 2/ 1929 Todd. 1,763,202 5/1930 Van Sickle. 

